One known way of reinforcing a pneumatic tire is to dispose, at the outer side in the tire radial direction of the crown portion of the carcass extending between bead portions, an inclined belt layer including cords extending at an inclination relative to the tire circumferential direction and a circumferential belt layer including cords extending along the tire circumferential direction.
In other words, the tire is reinforced for example by using the inclined belt layer to ensure rigidity in the tire width direction and to yield cornering power, which is one important index of steering stability, and by using the circumferential belt layer to ensure rigidity in the tire circumferential direction and suppress radial growth of the tire when driving at high speed.
In general, since a tire with larger cornering power has excellent steering stability, it is desirable to increase cornering power. Increasing the rigidity of the inclined belt layer in the tire width direction is an effective way of increasing cornering power. Specifically, steeply inclining the cords in the inclined belt layer relative to the tire circumferential direction is one possible approach.